High performance distributed objects using caching proxies for large scale applications
P. Martin, Vic Callaghan, A. D. Clark · 1999
Initial implementations of middleware based on standards such as CORBA have concentrated on host and language transparency issues in order to demonstrate interoperability. They have largely adopted a no-replication approach and have frequently neglected performance-at-scale issues. This has led to continuing deployment of either non-scalable full-replication approaches or ad-hoc messaging-based middleware for applications such as intelligent networks, WWW applications and collaborative virtual reality. These applications require millions of objects globally distributed across hundreds of hosts and demand a very high throughput of low-latency method invocations. Our main research aim is to be able to reason about the performance of such applications when using scalable partial-replication and object-oriented approaches to middleware. Our approach is to use a simulator to explore potential design and implemention choices. Our current simulator-driven design, called "MinORB", has been fully implemented and tested. MinORB supports scalable high performance by a combination of techniques, including weak and application-specified consistency and partial replication using fine-grained proxy caching. Experimental results show that our work compares very favourably with other leading implementations, such as OmniORB. Scalability is unparalleled, with up to 1,000,000,000 objects per address space, a maximum throughput of 42,000 invocations per second and service times as low as 4 ms.